any celestial object in our solar system whose orbit lies beyond Neptune, including Pluto: there may be some 70,000 trans-Neptunian objects orbiting 30–50 astronomical units from the sun, with diameters of at least 62 miles (100 km). Abbreviation: TNO
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Scientific definitions for trans-Neptunian object
A celestial object that orbits the sun at a greater distance on average than Neptune.
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